Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC 20008, USA.
Dallas Zoo, TX 75203, USA.
J Zoo Wildl Med. 2024 Mar;55(1):182-194. doi: 10.1638/2022-0046.
This study examined the viral shedding kinetics of elephant endotheliotropic herpesvirus (EEHV) in African elephants () compared to viral shedding behavior in Asian elephants (). Little is known about the transmission dynamics and epidemiology of this disease in African elephants. In light of recent clinical cases and mortalities, this paper aims to identify trends in viral biology. Trunk wash samples were collected from 22 African elephants from four North American zoological institutions that had recently experienced herd viremias or translocations. Processing of these samples included DNA extraction followed by qPCR to quantitate viral DNA load. The results were then compared with available literature that chronicled similar cases in Asian and African elephants. Minimal EEHV shedding was detected in response to varied herd translocations. Increased shedding was recorded in herds in which an elephant experienced an EEHV viremia when compared to baseline shedding. These index infections were followed by subsequent viremias in other elephants, although it is not known if these were recrudescence, transient controlled viremias, and/or primary infections via transmission to other elephants. When compared to historically published data, it was observed that EEHV3 cases in African elephants and EEHV1A cases in Asian elephants had consistently higher levels of viral DNA in the blood than were shed in trunk secretions, a fact that is seemingly inconsistent with such severe cases of disease and the high mortality rates associated with those respective types. The findings produced in this study highlight the need for more routine monitoring of viral shedding in African elephant herds to elucidate possible EEHV transmission and recrudescence factors for ex situ population management.
本研究比较了非洲象（）和亚洲象（）的象内皮疱疹病毒（EEHV）病毒脱落动力学，以了解这种疾病在非洲象中的传播动态和流行病学。鉴于最近的临床病例和死亡病例，本文旨在确定病毒生物学的趋势。从北美四个动物园机构的 22 头最近经历过群体病毒血症或转移的非洲象采集了象鼻拭子样本。对这些样本进行了 DNA 提取，然后进行 qPCR 以定量病毒 DNA 载量。结果与记录了亚洲象和非洲象中类似病例的可用文献进行了比较。在各种群体转移中，检测到 EEHV 的微量脱落。与基线脱落相比，当大象经历 EEHV 病毒血症时，记录到的脱落增加。这些指数感染随后在其他大象中出现病毒血症，尽管尚不清楚这些是复发、短暂控制的病毒血症和/或通过传播给其他大象的原发性感染。与历史上发表的数据相比，观察到非洲象中的 EEHV3 病例和亚洲象中的 EEHV1A 病例的血液中病毒 DNA 水平始终高于象鼻分泌物中的脱落水平，这一事实似乎与这种严重的疾病病例和相关类型的高死亡率不一致。本研究中的发现强调了需要更常规地监测非洲象群体的病毒脱落，以阐明可能的 EEHV 传播和复发因素，以进行原地种群管理。
